The smoking population in Vietnam has declined over the past five years, albeit at a slow rate, as officials say a smoking ban for indoor spaces have brought about changes.

Around 15.6 million Vietnamese still smoke, according to the 2015 Adult Tobacco Survey released Tuesday. That is 22.5 percent of the adult population, compared to 23.8 percent in 2010.

Phan Thi Hai, vice director of the Vietnam Steering Committee on Smoking and Health (VINACOSH), said the smoking rates have reduced among both men and women, especially in urban areas and at the workplace.

In particular the smoking rate among urban men has dropped from 45.3 percent in 2010 to 38.7 percent in 2015.

Nguyen Huy Quang, director of the Legal Department under the Ministry of Health, said relevant laws including a smoking ban at public indoor spaces have shown their effects.

The survey found the rate of secondhand smokers has reduced from 55.9 percent in 2010 to 42.6 percent in 2015, as fewer people smoke at medical facilities and schools and on public transport.

At the release of the survey, deputy health minister Nguyen Viet Tien stressed that up to 40,000 people in Vietnam die annually to smoking-related diseases.

Meanwhile, a survey at the National Cancer Hospital (K Hospital) in Hanoi showed 96.8 percent of lung cancer patients smoke.

“Scientists have recently found that smoking can affect future generations and change genes,” Tien said.